History
Historically, IC wafer manufacturing has implemented heating of IC wafer fabrication through the use of resistive coil heated hot plates. As illustrated in FIG. 1, the typical hot plate 10 includes a resistive coil 12, a main body portion 14, and a heating platform 16 for mounting the wafers upon.
Typically, there are several IC fabrication processes that require precise temperature control across the uniformity of IC wafers. For example, precise temperature control is required for resist thickness control during the soft bake process. Similarly, precision is required during critical dimension and "film speed" control on chemically-amplified resists occurring during post exposure bake processes.